The development of nanotechnology requires efficient ways for fabrication of micron and submicron structures on the same substrate. In many applications, it is desired to fabricate micro and nano structures that are connected.
One of the advantages of connected micro-nano structures is that micron structures can easily be addressed electrically, optically and mechanically allowing further addressing of the nano structures. There is also a great need for mechanical micro-nano structures, interfaces, definers, bridges that can be used on both planar and non-planar substrates.
There are numerous materials with properties that are interesting at supermicrometer, micrometer and submicrometer sizes, but that can not be patterned using conventional lithographic methods. Soft lithography (SL) represents a non-photolithographic patterning method based on self assembly and replica molding for carrying out micro- and nanofabrication. In SL an elastomeric material with patterned relief structures on its surface is used to generate patterns and structures that can be in the range of 30 nm to several cm. [Younan xia and George m. Whitesides, soft lithography mater. sci. 1998. 28:153-84]
One of the limitations in SL is the softness of the elastomeric material, which limits the aspect ratio of relief structures Aspect ratio can be defined as the height h (FIG. 1; 108, 112) of the relief structure divided by the width w (FIG. 1; 101, 107) of the structure (h/w). When h/w) is too low, the elastomeric material will deform/sag (See FIG. 6; 603/608). The sagging (608) of elastomers caused by compressive forces between the stamp and the substrate limits the use of most SL patterning techniques. The most common material used in SL is poly(dimethylsiloxane) (PDMS) which requires an aspect ratios >0.2 [Delamarche E, Schmid H, Biebuyck H A, Michel B. 1997. Adv. Mater. 9:741-46].
A number of prior arts for different techniques for patterning surfaces or materials deposited thereon without using conventional photolithography are known. An example of prior art is a paper by Zhang et al. [Zhang, L. G.; Liu, J. F. and Lu, Z. H. Micro fabrication on polymer with a contact procedure. Supramolecular Science, 5: 713-715 (1998)] discloses the fabrication of thickness-contrast micro-patterns based on a contact procedure. An array of PDMS micro-posts are constructed with grids which acts as the masters. This is also a contact procedure and the thickness-contrast micro-patterns on the polymer can be replicated to other substrates, such as silicon wafers, with microcontact printing.